Problem: $-pq + 8pr + 2p - 10 = 6q - 1$ Solve for $p$.
Solution: Combine constant terms on the right. $-pq + 8pr + 2p - {10} = 6q - {1}$ $-pq + 8pr + 2p = 6q + {9}$ Notice that all the terms on the left-hand side of the equation have $p$ in them. $-1{p}q + 8{p}r + 2{p} = 6q + 9$ Factor out the $p$ ${p} \cdot \left( -q + 8r + 2 \right) = 6q + 9$ Isolate the $p$ $p \cdot \left( -{q + 8r + 2} \right) = 6q + 9$ $p = \dfrac{ 6q + 9 }{ -{q + 8r + 2} }$